Fixation of Detached Osteochondritis Dissecans Lesions With Bioabsorbable Pins: Clinical and Histologic Evaluation

PurposeThe purpose was to evaluate the effect of fixation of detached free fragments of osteochondritis dissecans (OCD) (International Cartilage Repair Society OCD IV) on not only the clinical outcome, including functional and radiographic assessment, but also postoperative second-look arthroscopic and histologic evaluation.MethodsNine International Cartilage Repair Society OCD IV fragments were fixed with bioabsorbable pins made of poly-L-lactic acid after curettage of the bed and bone grafting. In 4 cases with severe cartilage damage in the fragments, after resection of the damaged part, trimmed fragments were fixed and osteochondral autologous transplantation was performed to cover the remaining defects. The follow-up period was at least 2 years (range, 2 to 3 years). Lysholm score and computed tomography (CT)/magnetic resonance imaging (MRI), second-look arthroscopy, and biopsy findings were examined postoperatively.ResultsAll patients ultimately could return to previous sports activity, and the mean postoperative Lysholm score was 97 (range, 90 to 100). At 6 months, CT/MRI scans showed complete union and smooth continuity of articular surface in all cases. Second-look arthroscopy in 7 cases showed that fixed fragments were stable and that there were no progressive degenerative changes in the cartilage. Postoperative histologic examination in 4 cases showed almost normal cartilage from surface to bottom in terms of viability and quality. In addition, new bone trabeculae were covering dead bone trabeculae, which is called creeping substitution.ConclusionsOur study shows good short-term clinical results, as well as confirmation of healing on CT/MRI and second-look arthroscopy.Level of EvidenceLevel IV, therapeutic case series.